Mercury switch and operating mechanism therefor



Oct. 4, 1932- P R T 1,880,831

MERCURY SWITCH AND OPERATING MECHANISM THEREFOR Filed Nov. 24, 1928 2 sheets-sheet 1 45 g}, Z940 54- lmnmummmumk 9 M I Mi I I -27 ilp l ll f 11mm"mamma m wmif 4633 ATTORNEL].

Oct. 4, 1932. P. K. CRAMBLET MERCURY SWITCH AND OPERA TING MECHANISM THEREFOR Filed Nov. 24. 1928 2 Sheets-Sheet 2 INDENTOR. %M/( I Mum / ATTORNEI].

5'0 mercury switch is provided which includes Patented Oct. 4, 1932 UNITED STATES PATENT OFFICE PAUL K. CRAMBLET, 0F MILWAUKEE, WISCONSIN, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO MINNEAPOLIS-HONEYWELL REGULATOR COMPANY, OF MINNEAPOLIS, MINNE- SOTA, A CORPORATION OF DELAWARE MERCURY SWITCH AND OPERATING MECHANISM THEREFOR Application filed November 24, 1928. Serial No. 321,566.

This invention relates in general to mercury switches and operating mechanism therefor particularly designed and adapted for use as a sign flasher.

One of the principal objects of the present invention is to provide a device of this character which is of simple and durable con struction and which is effective to rapidly make and break a plurality of electrical circuits in predetermined succession, thereby enabling the use of the device as a sign flasher which controls the operation of the so-called chasing border of an electric sign. The switch also possesses capacity for use in various other diverse applications.

The rapid making and breaking operations required in the mercury switch of a sign flasher as Well as in certain other applications may be effected in highly satisfactory and eflicient manner by displacing the mercury under the influence of centrifugal force and utilizing this force to cause the mercury to successivel coact with a plurality of elec-' trodes. as to subject the mercury therein tothe action of the centrifugal force, presents, rather a difficult problem, because the use of brushes and commutator bands ishighly undesirable and the most effective and satisfactory method-of connecting up'the electrodes of the switch with the externalcircuits is by means of flexible leads. The use of such leads precludes the rapid rotation of the switch for the purpose of subjecting the mercury to the action of centrifugal force as rotation of; the switch would wind the leads there about. Obviously, it is desirable to flex the leads as little as possible and yetat least v the portion of the switch containing the mercury must be moved bodily if the mercury is to be subjected to the action of a centrifugal force. The present invention provides a simple, durable comparatively inex-' :pensive and practical organization which subjects the mercury to the action of cen- -trifugalforcewhile minimizing flexion of the a capacity for oper--' v --ation-at :varia'ble speeds.

cleadsrand while having @mIn: carryingv out the present invention a anipulating a mercuryswitch so The tutes the rotor of an induction motor.

field pieces of the motor straddle the periphery of the disk and at least one of them is adjustable to secure the desired variation in the speed of operation.

Other objects and advantages reside in certain novel features of the construction,

arrangement and'combination of parts which will be hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawings forminga part of this specification, and in which:

ing a'device embodying the present invention;

Figure 2 is a view thereof in side elevation; Figure 3 is a View thereof in top plan; Figure 4 is a view in horizontal section taken on line 44 of Figure 2;

Figure 5 is a fragmentary view partly in elevation and partly in section along line 55 of Figure 1, the mercury switch and its grippers being omitted for the sake of simplicity of illustration;

Figure 6 is a detail view in section taken on line 66 of Figure 4;

Figure 7 is a view in diametrical vertical section illustrating the mercury switch employed; and 4 Figure8 is a transverse section taken on line 88 of Figure 7.

Referring to the drawings wherein for the sake of illustration isshown one embodiment of the invention, the numeral 1' designates generally a mercury switch, having (see Figures 7 and 8) an outer envelope 2 in which a series of wells 3 of arc resisting material are provided Electrodes l, 5, Band 7 are sealed in through the outer envelope and Figure 1 is a view in front elevation show:

project down into the wells, the portions of the electrodes above the wells being protected by protective sleeves 8 of suitable glass or other composition. A body of mercury is designated at 9 and fills the lower portion of the envelope 2 and also has portions filling the wells 3. A central electrode 10 is also sealed through the envelope and extends down through the plate carrying the wells and is immersed in the main body ofthe mercury. This central electrode may consist of two strands of wire which below the plate are bent outwardly thereunder as at 10 and have their terminals engaged in peripheral notches in the plates as shown at l (Figure 8) so as to provide a support and holder for the plate. A glass protective sleeve 12covers the electrode above the plate. The novel characteristics of this type of mercury switch are fully described and claimed in the copending application of Paul K. Cramblet for mercury switches executed under even date herewith. While this particular switch may be advantageously utilized in connection with the apparatus forming the subject matter of this invention and application, it is to be understood that the construction of the switch may be varied, and so far as the internal construction is concerned, theswitch may have characteristics similar to those of the rotary type of switch fully described in the copending application of Paul K. Cramblet for mercury switches filed August '20, 1927, Serial No. 214,233. For the purposes of the present invention, it is sufficient to have a mercury switch which has an outer envelope, a plurality of electrodes therein, and a body of mercury successively cooperable with the electrodes under theinfluence of centrifugal force. Usually a single electrode is immersed in the main body of the electrode and the remaining electrodes are immersed in the mercury contained in the wells so as to provide a mercury to mercury make and break, but obviously the shiftable body mercury may be caused to successively contact directl with exposed rigid metal electrodes if it 1s desired to utilize such an arrangement.

The operating mechanism for the mercury switch comprises a base 15 provided with a bearing 16 and having a standard 17 extend-- ing upwardly from its rearward portion and formed with an arm 18 which overhangs the bearing 16. A short vertical shaft 20 is rotatably mounted in the bearing 16 and its lower end bears upon a ballbearing 21 (see Figure 5). Above the bearing 16, the shaft 20 is fixed to a collar 22 as by means of a set screw 23 and the collar, in turn, is secured by 'screws 24 to a metallic disk 25. The disk 25 constitutes the rotor of an induction motor of conventional construction except for the adjustable mounting provided for one of its field pieces and designed to provide for speed variation. Thus, as shown ,in the drawings,

the motor includes not only the disk 25 but a fixed field piece 26 disposed below and adjacent the outer periphery of the disk and having its laminated core projecting beyond its windings and secured at its lower end to the standard 17 as indicated at 26. An adjustable filed piece is designated at 27, and is carried by a bracket 28, the laminated core of the field piece 27 pro]ecting beyond the field windings and being fastened by screws 29 to angular lugs 30 of the bracket 28 (see Figures 3 and 4). The body of the bracket 28 is provided with spaced longitudinally extending slots 31 through which screws 32 extend. The screws 32 not only pass through the slots 31, but also pass through the openings of a resilient gripping plate 33 (compare Figures 4 and 6) and are then threaded through an arm 34 and into the standard 17. The gripping plate 33 is curved transversely as shown in Figure 6 so that when the screws are tightened up the heads of the screws press the plate 33 against bracket 28 and the bracket 28 against the arm 34 thereby tending to releasably hold the bracket 28 in adjusted position and securing the arm 34 to the standard 17. Adjustment of the bracket 28 is effected by means of an adjusting screw 35 swiveled as at 36 on an angular extension 37 of the arm 34- and threadedly connected as at 39 with one of thelugs 30 of the bracket 28. The screw 35 is formed with a knurled head 40 to facilitate adjustment thereof. When the screw 40 is turned, it moves the bracket 28 lengthwise thereby moving the pole-piece or field piece '37 laterally with respect to the disk 25 and with respect to the underlying pole-piece or field piece 26.

From the fore oing it will be understood that when the fiel pieces 26 and 27 are appropriately connected up with a suitable source of alternating current, the disk 25 will be rotated. Thes eed of rotation is varied by adjusting the eld piece 27.

The rotation of the'disk 25 is utilized to so operate the mercury switch as to displace the main body of the mercury angularly therein under the action of centrifugal force, therebycausing the main body of mercury to suecessively make and break contact with mercury in the well 3. In carrying out this purpose, a holder designated generally at is provided for the switch 1, the body of the holder having spring clips 46 suitably fixed thereto and equipped with yieldable gripping pads 47 designed to grip and hold the enstud 50 fixed thereto and engaged in a suitably i shaped bearing recess 51 formed in the collar 22 at a point spaced from its center (see a Figure 5). This provides a driving connec* tion between the rotor of the induction motor and the holder and the driving connection so provided is eccentric to the rotor whereby rotation of the disk moves the lower end of the holder bodily in an endless path. The upper end 18 of the holder has a socket piece 52 rigidly secured thereto and engaged by the rounded lower end 53 of a stud 54 threaded in the arm 18 and secured in position by a lock nut 55. The socket 52 and stud 53 are located in alignment with the shaft 20, that is, with the axis of rotation with the disk 25. While the socket 52 and stud 53 permit rocking movement of the upper end of the holder, rotation of the upper end of the holder is prevented by means of a U-shaped spring member 56 having the end of one leg fixed as at 57 to the arm 18 of the standard and having the end of its other leg fixed as at 58 to the upper end of the holder. While this spring member 56 is yieldable or flexible in a direction to permit tilting or rocking of the upper end of the holder, it prevents rotation of the upper end of the holder.

The standard 17 and arm 18 carry a terminal board 60, the arm 17 having an integral laterally directed lug 61 to which theupper end of the board secured as indicated at 62 while the lower end of the board is fixedly supported upon the standard by means of a bolt 63 and bushing 64 (compare Figures 1 and 3). The flexible leads which are connected up to the electrodes 4, 5, 6, 7 and 10 are fastened to binding posts provided on the terminal board. The lamps are connected up to one side of the power line and are also connected to the binding posts on the terminal board which are connected to the electrodes 4, 5, 6 and 7. The other side of the power line connects to the binding post on the terminal board connected up to the electrode 10. The circuit involved is similar to that disclosed in the Cramblet application 214,373 above referred to. The induction motor is appropriatelyconnected up to the power line through binding posts of the terminal board. As the electrodes and flexible leads extend in through the upper end of the envelope of the switch. they are subject to minimum flexion since this upper end simply rocks and does not rotate or move bodily in an endless path.

From the foregoing. it will be understood that when the disk 25 rotates, the mercury switch partakes of the endless bodily motion imparted to the lower portion of the holder and consequently the mercury in the switch is subjected to the action of centrifugal force and responding to this force moves angularly within the envelope and successively contacts with the mercury in the wells so that the electrode 10 constantly immersed in the shiftable portion of the mercury is successively electrically connected with the electrodes 4, 5, 6 and 7 covered by the portion of the mercury filling the wells 3.

The invention claimed is:

1. In a sign flasher, operating mechanism for a mercury switch of the type having its mercury successively cooperable with a series of electrodes when subjected to the action of centrifugal force comprising a motor driven disk, a holder upon which the switch is intermediately positioned and supported, said holder having one end constrained to rock about a point aligned with the axis of rotation of the disk and having its other end eccentrically connected to the disk.

2. In a sign flasher, operating mechanism for mercury switch including a rotatable element, a holder for'the switch having one end constrained to rocking movement and having its other end eccentrically and positivel connected to the rotatable element and odily rotated thereby.

3. In a sign flasher, operating mechanism for a mercury switch of the type having its mercury displaceable angularly within the switch for effecting switch operation, and comprising a rotatable element, a holder for the switch, a driving connection between one end of the holder and the rotatable element whereby the holder is moved in an endless path upon rotation of the rotatable element and means for constraining the other end of the holder to rocking movement.

4. In a sign flasher, operating mechanism for a mercury switch of the type having its mercury successively cooperable' with a plurality of electrodes under the action of centrifugal force, and comprising a rotatable element, a holder for the switch, a driving connection between the lower end of the holder and the rotatable element whereby the holder is moved in and endless path upon rotation of the rotatable element, means for mounting the upper end of the holder for rocking 'movement thereof, and yieldable' means preventing rotation of the upper end of the holder while permitting rocking thereof.

5. In a sign flasher, operating mechanism for a mercury switch of the type having its mercury successively cooperable with a plurality of electrodes under the action of centrifugal force, and comprising a rotatable element, a holder for the switch having offset ends, switch gripping means between the ends, an eccentric driving connection between the oflset lower end and the disk, means cooperable with the upper ofi'set end to permit rocking movement thereof, and yieldable means preventing rotation of the upper end of the holder while permitting rocking thereof.

In witness whereof, I-have hereto affixed my signature.

' PAUL K. CRAMBLET. 

